Welding Neck Flange Bore Chart [with PDF]

Welding Neck Flange Bore Chart [with PDF]

This table is a common bore size table for weld neck flanges. It lists the size data of flanges with different nominal pipe sizes. At the bottom you can choose to download this form so you can view it at any time.

Normal Pipe SizeODSCH 10SCH 20SCH 30STD WALLSCH 40SCH 60EXT HVYSCH 80SCH 100SCH 120SCH 140SCH 160XX HVY
1/20.840.6740.6220.6220.5460.5460.4640.252
3/41.050.8840.8240.8240.7420.7420.6120.434
11.3151.0971.0491.0490.9570.9570.8150.599
1 1/41.661.4421.381.381.2781.2781.160.896
1 1/21.91.6821.611.611.51.51.3381.1
22.3752.1572.0672.0671.9391.9391.6871.503
2 1/22.8752.6352.4692.4692.3232.3232.1251.771
33.53.263.0683.0682.92.92.6242.3
3 1/243.763.5483.5483.3643.3642.728
44.54.264.0264.0263.8263.8263.6243.4383.152
55.5635.2955.0475.0474.8134.8134.5634.3134.063
66.6256.3576.0656.0655.7615.7615.5015.1874.897
88.6258.3298.1258.0717.9817.9817.8137.6257.6257.4377.1877.0016.8136.875
1010.7510.4210.2510.13610.0210.029.759.759.5629.3129.0628.758.58.75
1212.7512.3912.2512.091211.93811.62611.7511.37411.06210.7510.510.12610.75
141413.513.37613.2513.2513.12412.8121312.512.12411.81211.511.188
161615.515.37615.2515.251514.6881514.31213.93813.56213.12412.812
181817.517.37617.12417.2516.87616.51716.12415.68815.2514.87614.438
202019.519.251919.2518.81218.3761917.93817.4381716.516.062
222221.521.2521
242423.523.2522.87623.2522.62422.0622320.93820.37619.87619.312
262625.2525
303029.3762928.7529.2529
363635.3763534.7535.2534.535
404039.2539
424241.2541
484847.2547
  • All dimensions are in inches
  • These dimensions are the same for the inside pipe diameter. ALWAYS specify bore when ordering
  • Other types, sizes, and thicknesses of flanges can be provided to meet application
[Excel] Weld-Neck-Flange-Bores-Chart.xlsxDownload
[PDF] Weld-Neck-Flange-Bores-Chart.pdfDownload

Column information in the table

  • Nominal Pipe Size (NPS): Nominal pipe size, which indicates the size of the pipe in inches.
  • OD (Outside Diameter): The outer diameter of the flange in inches.
  • SCH 10 to SCH 160: These columns represent flange sizes with different wall thickness grades. “SCH” is the abbreviation for “Standard Pipe Wall” which refers to the standard thickness of the pipe wall. The larger, the thicker.
  • STD WALL (Standard Wall): Standard wall thickness. This is the most common wall thickness grade and is suitable for general pressure and temperature conditions.
  • EXT HVY (Extra Heavy): Extra heavy wall thickness. This wall thickness grade is thicker than the standard wall thickness and is suitable for higher pressure and temperature conditions, or where additional strength is required.
  • XX HVY (Double Extra Heavy): Double Extra Heavy Wall Thickness. This wall thickness grade is thicker than Extra Heavy Wall Thickness (EXT HVY) and is suitable for occasions requiring extremely high pressure and temperature conditions.

Each row of data represents the size of the flange corresponding to the nominal pipe diameter and wall thickness grade. For example, for a flange with a nominal pipe diameter of 1/2 inch, if the wall thickness grade is SCH 10, its inner diameter (Bore) is 0.622 inches and its outer diameter (OD) is 0.840 inches.

Author: Lewis Liu

Hello, my name is Lewis Liu, and I’m a professional sales engineer with over a decade of expertise in the flange fittings sector.

I am quite informed about flange selection, installation, and maintenance. I am passionate about providing customers with the greatest solutions for keeping their pipeline systems running smoothly, safely, and dependably.

If you have any queries or concerns concerning flange fittings for your pipelines, whether they are about selection, material choice, specification requirements, or anything else, please contact me at any time. I am dedicated to providing expert advice and assistance to help you make educated decisions and reach your objectives.

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